To solve for the number of terms ($n$) in the arithmetic progression, we can use the formula for the sum of the first $n$ terms:

$$S_n=\frac{n}{2}\times (a+l)$$

Where:
- $S_n$ is the sum of the first $n$ terms
- $a$ is the first term
- $l$ is the last term
- $n$ is the number of terms

Given:
- $S_n=252$
- $a=-16$
- $l=72$

Substituting the values into the formula:

$$252=\frac{n}{2}\times (-16+72)$$

Simplifying:

$$252=\frac{n}{2}\times 56$$

Multiply both sides by 2 to eliminate the fraction:

$$504=56n$$

Solve for $n$:

$$n=\frac{504}{56}=9$$

Thus, the number of terms in the series is D. 9.